The invention relates to the mining industry and can be used for working out mineral deposits not depending of their thickness and bedding angle.
In the prior art there is a known method for mining of deposits which includes the carrying out of mining works by an openwork method with the use of self-propelled machinery, over-passing rock bulk into underground mine workings worked out earlier and subsequent hoisting thereof over a conveyer slope to the surface (U.S. Pat. No. 4,103,972; US C1. 299/18, 1978).
There is also a known method of the openwork of deposits which provides the breaking of main reserves by blasting holes from the surface of steps and the transporting of the rock bulk to the surface. The descending blast holes for breaking the ore are drilled from the open cut""s bottom (V. N. Synchkovsky, xe2x80x9cTekhnologia otkrytykh gornykh rabotxe2x80x9d [The technology of mine openworks], Krasnoyarsk, Krasnoyarsk State University, 1989, p.p. 356-358).
Disadvantages of the known solutions are:
the necessity of a preliminary construction of the whole complex of underground mining out works for transporting the broken rock bulk to the surface that involves substantial capital initial expenditures and postpones time limits of putting into operation thereof;
the substantial volume of overburden operations due to the impossibility of forming an open cut with a steep final angle of a flank.
It is an object of the invention to provide a reduction in the volume of overburden operations owing to a steep angle of an open cut flank""s run.
This is accomplished owing to that, in a method of the openwork of deposits which provides the breaking of main reserves by blasting descending holes from the surface of steps and the transporting of the rock bulk to the surface, the working our of levels"" reserves being done with forming a vertical or close to vertical, slope of one of an open cut""s flanks within a definite level, for that, near a contour thereof, a safety prism is being formed, the breaking of which is being done at the final stage of works on the level, and rocks beyond the open cut""s contour and located within a zone of possible displacement of the open cut""s flank are reinforced by prestressed anchors and/or by injecting binding grouts via holes, the main reserves of levels are being worked with self-propelled machinery being involved, remote control equipment being used for working out the safety prisms, the resources thereof are extracted by selective methods, the rocks, being beyond the open cut""s contour and located within a zone of possible displacement of the open cut""s flank, are being reinforced by separate portions located discretely or by a continuity on the whole surface of possible displacement of the open cut""s flank, the rock being near the contour are being reinforced additionally by means of preliminary pumping of binding grouts and/or by installation of anchors, vertical or close to vertical, slopes of a steep flank are being formed, the injecting of rock is being carried out by pumping grout via holes drilled through the body of the safety prisms, into rocks being located beyond the open cut""s contour, steel ropes arranged to be disposed on the earth surface and anchored beyond the displacement with the ends thereof monolithed at various depths, the safety prisms being drilled out by horizontal or ascending holes, in the body of the safety prisms there are mine working from which the drilling out of these prisms is being carried out as well as works for reinforcing rocks in the zone of possible displacement of the open cut""s flank, the injecting of binding grouts is being carried out through vertical and curve holes drilled from the surface, and a safety bench of steep flank is being formed for several levels.
The order provided for carrying out the work allows to form, within a level, a vertical or close to vertical angle of a flank""s run. This has become possible by virtue of that the safety prisms formed within the level being worked out along the entire flank prevent the occurrence of emergency situations caused by probable local cavings of rocks, when combined with the order provided for carrying out the work related to extraction of reserves of said safety prisms, and additional measures taken to improve the stability of the zone the mass of rocks around the contour to ensure the stability of that mass throughout the entire period of the operation of the mining enterprise.
The indicated object and advantages of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings.